Trimmer for abrasive disks



1943- A. SMITH 5 TRIMMER FOR ABRASI VE DISKS Filed July 23 1942 Patented Nov. 9, 1943 UNITED STATES PATENT 0F TRIMMER FOR ABRASIVE msxs Lawson A. Smith, Long Beach, Calif. Application July 23, 1942, Serial No. 452,113

3 Claims.

This invention relates to and has for an object the provision of a novel and highly efiicient machine for quickly, easily and accurately cutting away the worn out marginal portions of flexible circular abrasive disks for the purpose of forming new and unused marginal portions having the abrasive effectiveness of new disks of corresponding diameters.

An important object of this invention is to provide a trimming machine of the character de: scribed in which novel shearing cutters and an adjustable disk holder are constructed and arranged to make possible a quick, easy and accurate cutting away of worn out marginal portions of varying widths and in disks of diiferent diameters.

Another object of my invention is to provide a trimming machine such as described in which the disk holder isadapted to be swung from an outof-the-way position with the disk thereon into a predetermined position where it comes to rest with the abrasive disk so presented and engaged with the shearing cutters that the action of the cutters will hold the disk in said predetermined position and rotatably feed the disk to the cutters while the trimming operation is taking place, it being unnecessary for the operator to guide, rotate or hold the disk after the trimming operation is started.

Heretofore it has been a common practice pivotally to support the disk being trimmed between the open end portion of a U-shaped or yoke shaped frame, but it is an object of this invention to simplify such structures by doing away with the overhanging portion of the means for supporting the disk.

With the foregoing objects in view, together with such other objects and advantages as may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and illustrated by way of example in the accompanying drawing, in which:

Fig. 1 is a fragmentary top plan view of the trimming machine embodying my invention;

Fig. 2 is a fragmentary side elevation of the machine shown in Fig. 1;

Fig. 3 is a sectional view taken on the line 33 of Fig. 1;

Fig. 4 is a sectional view taken on the line ii-4 of Fig. 2.

Referring to the drawing more specifically, l designates an elongated base plate adapted to be secured as by means of fastenings 2 to a bench, table or like support 3.

On this base plate are mounted a shearing cutter mechaanism A and a holding means B, the latter being adapted to supporta flexible abrasive disk of circular form such as the one Q here shown in Figs. 1 and 2 and which is to be trimmed to remove the worn marginal portion indicated at C".

The cutter mechanism hprimarilyincludes a pair of rotary circular cutters 4 and 5 arranged in overlapping relation to, produce a shearing cut as best shown in Fig. 3:. These cutters fare fixed on shafts B and l journalled in a U-shaped bracket 8 secured to qne end ofthe base i. As here provided the shafts are rotated in opposite directions by means of meshed gene. 3 and ill thereon and a crank handle' l I fixed to theupper shaft 6. However, it is obvious that these shafts could be power driven if desired. The lower shaft 1 is held against axial ihbvment by means of the stop collars l2 and I3 abutting the bracket 8 whereby the cutter 5 is in a fixedpositbn. The upper shaft 6 is likewise fixed against axial move.- ment by means of .the stop collar It and the gear 9; but the cutter 4 is splined thereon and yieldable axially by reason of the spring [:5 which urges said cutter against the cutter 5 and main tains two cutters in proper position to .erreg a shearing out upon being rotated. Moreover, these cutters grip and rotate the disk thereby feeding the disk between them while the trimming operationis taking place. I I I I V The disk holding means B includes an mp5 Wardly offset supporting and guide member i5 forming a part of the base i andhavinga ner;- tudinal slot ll therein whiclri is parallel to the axes of the cutters 4 and 5'. A disk holdermerii ber iii in the form of a rectangular plate is /mounted on the memb r .16 for axial adjustment toward and away from the cutters and for .sWifiging movement to bringthe dis'k in an arcuate movement between the cutters in starting' ,the' cutting operation. l 1

Mounted to rotate freely near one end of the; holder member l8 isya pi es 4e havinga coni'al upper end [9' adaptedqto extend through the center hole 2| in the disk C whereby the disk is rotatably supported on and may be moved with the holder.

As a means for pivotally and slidably mounting the holder ill on the supporting member l6,

a set screw 22 is inserted through an opening 23 near one end of the holder I8, also through the slot [1 and has a T nut 24 threaded on its lower end. The nut 24 is provided with a flat sided. shank 24 slidably and non-rotatably engaged in the slot I! while the head of the nut lies against the under side of the member IS. The set screw 22 has a bearing portion 2 2 on which the holder l8 is pivotally mounted. A shoulder 22" on said screw clamps against the upper side of the member It so that in cooperation with the nut 24 a clamping device is provided which grips the slotted portion of the plate l6, and the member 18 may be set and held in adjusted position by said clampingdevice to determine the extent or width of the trim while the holder is free for pivotal or swinging movement about the bearing portion 22 without disturbing the set'of the holder. r

In the operation of the trimmer the holder 18 is adjusted according to the widthof themarginal portion of the abrasive disk that is to be.

cut ofi and then set in the proper position by tightening the set screw 22. The holder is then swung to one side as shown in dotted lines in Fig. l, and the disk C is mounted on the-pintle l9;following which the holder is swung back over the member l6 into alignment therewith to move the disk arcuately between the cutters 4 and 5.

A stop pin 26 on the holder I8 engages the member IE to limit the movement of the holder to a position in alignment with the member I6. Once the disk is engaged between the rotating cutters 4 and 5, the disk will be gripped and rotatably fed between said cutters during the cutting operation and the desired marginal trim of the disk will be efiected without requiring that the operator touch the holder H3 or the disk C.

It should be noted that the action of the cutters 4 and 5 causes the holder I8 to remain with the stop pin 26 abutting the member l6; thereby automatically maintaining the holder and disk in the proper position during the trimming operation. 7

It will now be apparent that with my novel trimmingmachine it is possible to quickly, easily, accurately and with a minimum of cost trim off the worm marginal portions of abrasive disks and the like. of various sizes to restore such disks to usefulness; and that it is easy to mount and remove the disks because no portion of the machine obstructs the space above the mounte disk. 7

While I have shown and described a specific embodiment of my invention I do not limit my self to the exact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

' 1. In a machine for trimming circular disks, rotatable circular shearing cutters, means for rotating said cutters, a supporting member in fixed relation to said cutters comprising an elongated plate having a longitudinal slot therethrough extending parallel to the axis of said cutters, a holder for a disk to be trimmed'having a pintle adapted to rotatably support the disk, a pivot member slidably adjustable along said slot and on which the holder is pivoted to swing into and out of a position in which the disk will be engaged with and between said cutters; means carried by said pivot member for releasably holding it in said slot while the holder is free to pivot thereon,

said holding means comprisingclamp portions to grip between them the slotted portion of said plate; and a stop member extending downwardly from said holder between said pintle. and said pivot member adapted to engage said supporting member to limit the movement of said holder to a position in which the disk will beengaged and trimmed by the cutters.

2. In a machine for trimming circular disks,

. a support, a pair of cooperating, rotatableclrcular shearing cutters mounted on said support, means for rotating said cutters, a hired elongated plate having a longitudinal slot therethrough extending parallel to the axes of said cutters, a holder for a disk to be trimmed comprising an elongated member having'a pintle upstanding from one of its end portions to rotatably support the there being anunobstructed space above the disk when it is supported upon said pintle, a pivot member slidable in said slot and on which the opposite end portion of saidholder isjpivoted to swing to and from a position in which the disk will be engaged with and between said cutters;

means carried by said pivot member for releasably holding it in said slot while the holder is free to pivot on said member, said holding'means comprising clamp portions to grip between them the slotted portion of said plate; and stop'means to limit the'movement of said holderto a posigated member having a pintle upstanding from one of its endportions to rotatably support the disk,there being an unobstructed space above the disk when it is supported upon said pintle, a set screw having one -of its end portions screw threaded and a head at its opposite end, saidset screw having between its head and screw threaded part an unthreaded portion which is of greater diameter than the width of said slot and is turnably fitted within a hole through-that end portion of said elongated member which is 1'ar-.

thest from the aforesaid pintle, and a nut having a shank portion which occupies the aforesaid slot and. is slidably adjustable therealong, said nut having a body portion which cooperates with said unthreaded portion of said screw to perform a clamping action against opposite sides of said slotted plate, and stop means to limit the swing of said elongated member upon which" the'disk: I

to be trimmed is mountable. j

LAWSON A. 

